Replace Grundfos UP 10 Pump with UP 10-16 PM

[Baumgrenze]

Our house is a single story on cement slab post-and-beam built in 1955. The copper water lines are in/or under the slab floor, and emerge through holes in the wall sill for connection.

My venerable UP10 16B5/TLC (P/N 96433895) seems to have finally died. I simply ran it on a 20" on/20" off cycle during the hours we thought we wanted hot water 'on demand' in a very remote master bathroom. We have a dedicated, insulated return

I'm having trouble installing a replacement.

I picked up the current pump, UP 10-16 PM, which uses temperature to decide when to run rather than a timer. It came with a 'pictographic' installation manual. I must be 'image challenged' but what I am too do with what I believe is the 'detector' that tells the pump when to run. The drawing on page 12 of the manual seems not to account for my dedicated return line.

Should the detector really be on the water line that leaves the top of the water heater? I'd be more inclined to put it near the pump, which returns water to the water heater. If water at that point in the loop is hot, I know I will have hot water in the master bath.

Page 13 of the manual shows the power cord emerging towards the floor and seems to say, you can only run the detector cable off horizontally; there is a red X on a pictograph with the cable going towards the floor.

Does this 'detector' system really work? Could I install a clock timer on the power and set the pump to 'run 100% during the hours I want service (like in the past.) I'm pretty sure that I'd need to be careful that the timer could take the inductive load presented by the pump motor, 1/25th HP.

Has anyone else had experience with an installation like mine?

thanks

baumgrenze

 

[hj]

I have no idea what this "detector" is. How about a photo of it, and/or the manual's page.

 

[Sponsor]

 

[Baumgrenze]

Thanks for asking. I will try. These open for me.

Page 12 which shows the 'device' (the inset on the left). It is strapped to the pump with the instruction, 'see the manual.'

http://imgur.com/UEfJvhR

Page 13 which suggests that the 'device' should only be pulled out horizontally (lower right inset)

http://imgur.com/uzeTcQR

thanks
baumgrenze

 

[CountryBumkin]

I hate those pictographs instructions. At least all languages are equally confused.

That pump has a temperature sensing probe. The second picture shows rotating the pump's body so the sensor lead is horizontal (not coming off bottom).

I have a Grundfos model UP10-16BN5AT/ATLC p/n 96433899 (has the built in rotary-dial timer). Never used. If this is what you need PM me.

 

[Reach4]

Page 13 which suggests that the 'device' should only be pulled out horizontally (lower right inset)

Yet the first picture shows it vertical. I am suspecting that the second picture is saying to not support the pipe by applying tension to the probe cord. Maybe it is saying something else, for all I know.

On http://www.pexuniverse.com/docs/pdf/gr-up10-16-installation-manual.pdf , the picture under the level icons seems to make it clear that you can swivel the cord direction including down.

 

[Baumgrenze]

Maybe this will clarify my working situation. I stopped and made a scale elevation drawing of my water heater and the associated water circulation plumbing. I marked all the tees with an X to allow image lines to cross. I drew 'hot' lines in red and cold and/or returning recirculation lines in blue to set them apart from one another. This plumbing was installed in a 2010 remodel. The original Laing pump failed in 2014 and was replaced at no cost to me with a 'recycled' Grundfos with the comment that they are well made products. I've had a Grundfos on my hydronic heating since 1980 with no complaints yet.

My best recollection is that the wider, shorter U drop (on the left) was installed in 2014 as a backflow preventer. Does this make sense to experienced plumbers? In putting this together I also came to the conclusion that the water heater installer placed the isolation ball valve in the wrong place. I think it should be between the tee and the water heater connection. Am I wrong?

Here is a link to the sketch:

http://imgur.com/aq2xaPM

thanks,
baumgrenze

 

[CountryBumkin]

I'm not a pro -
I don't understand your drawing. The recirculation pump is pulling cold water from the "return" line coming from bathroom pumping it back into the cold side of your plumbing system. What does the "J loop" do?

What I expected to see was the pump pushing the water back into the heater at the WH cold supply connection with a check valve (pump may have built in check valve - but I don't think the Grufundos pumps have one) so that the return water can only enter the WH.

What keeps the warmer return water from flowing back to the bathroom? Do you get cold water in the bathroom?

 

[Baumgrenze]

Thank you for persisting with me.

I am in the process of drafting a letter to the plumber who last worked on the system and installed a new water heater in 2014. I hope to persuade him to write a few explanatory notes on a copy of the drawing and send it back to me in a stamped, self-addressed envelope.

I believe he has all the business he can handle working as a plumbing sub-contractor for several local general contractors. I like him. He is no-nonsense but I find I can no longer reach him by phone...

He replaced a failed Laing recirculation pump #? (7/10 - 12/13) with the Grundfos UP 10 16B5/TLC (P/N 96433895) I used from 12/13 - 3/17 by reusing the 'mounting plate' for the Laing. I checked with the local Laing distributor and this part does not have an integral check valve. The new Grundfos I am considering installing came with a 'mounting plate' which incorporates a check valve, but I cannot install it because it has larger union fitting (Now that I look carefully, I am no longer confident I should try to mount the new pump on the Laing mounting plate. Perhaps the Grundfos I was running was not really meant to pair with it even though the lock nut tightened it in place just fine. I looked and the Laing has a black, plastic interior that superficially looks a lot like the brass Grundfos interior.) The copper lines are 1/2". The union fittings that mate with the mounting plate are ~1" in the male thread for the union nut. The union fitting on my new pump are 1.57" in the corresponding male threads. I need to research thread sizes for pipe every time I contemplate a project!

In answer to your questions, I certainly do not have a deliberate check valve. If my aging memory serves me correctly, the 33" J-loop was installed to prevent back flow. If the drawing is not clear enough, the cold water supply from the city enters a tee. One leg of the tee delivers cold water to a new bathroom adjacent to the furnace room. The other leg passes through the 33" J-loop on its way to the cold inlet on the water heater. On the way it encounters a tee (high up in the room) that connects it effluent from the pump in the 72" J-loop containing the pump. Before it reaches the cold water inlet it is also connected to an expansion tank.

When everything was working fine, there was cold water in the new bath. The only tap in the house with tepid 'cold' water was in the kitchen. It is the first connection to the long delivery lines to the original bathrooms, in remote corners on the same side of the house. I decided that was caused by the hot and cold lines running fairly close to one another in that part of the circulation.

Thanks again,
baumgrenze